Closed-loop, dome-shaped, thermal energy storage system

ABSTRACT

A thermal energy storage system comprising a dome-shaped thermal storage medium, a power supply that provides electrical power to an electrical air heater, a heat exchanger, an air blower, a steam generator, a tower, and air return duct. The thermal energy storage system may be designed in such a way that air return ducts are used to allow heat to travel back to the thermal storage medium, thereby improving efficiency and reducing loss of heat or energy of the system.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.63/348,444, filed on Jun. 2, 2022, which is incorporated herein in itsentirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT

Not applicable.

INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not applicable.

BACKGROUND OF THE INVENTION

The transition to inexpensive, but intermittent, wind and solar energydemands gigawatt-hours of storage that can then be delivered at themegawatt power level on demand. Because of the looming climate calamity,it will be necessary to cease the burning of fossil fuels. With growinginterest in renewable energy resources such as wind and solar energy,there remains the question of how to effectively utilize the currentlyfossil fueled, industrial settings. Therefore, development of longduration, geographically and spatially agnostic, cost competitive energystorage technology is needed, especially if it can integrate the currentinfrastructure of the fossil fueled industrial settings.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, the present invention concerns thermal energy storagesystems and methods. In particular, the present invention relates to theconversion of fossil-fuel-powered plants into zero-carbon renewableenergy storage facilities.

In another embodiment, the present invention concerns an efficientthermal energy storage system wherein the system is designed to allowthermal energy to be stored within a dome-shaped thermal storage mediumcapturing the buoyant heat, thereby improving efficiency of the system.

In another embodiment, the present invention concerns a thermal energystorage repository with a reversible air blower, electrical heater,steam generator placed in a single heat exchanger duct wherein the heatexchanger duct is horizontally configured.

In another embodiment, the present invention concerns a thermal energystorage method for efficient operation of the thermal energy storagesystem.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe substantially similar components throughout the severalviews. Like numerals having different letter suffixes may representdifferent instances of substantially similar components. The drawingsillustrate generally, by way of example, but not by way of limitation, adetailed description of certain embodiments discussed in the presentdocument.

FIG. 1 is a schematic view of a thermal energy storage system.

FIG. 2A is a perspective view of a preferred embodiment of a thermalenergy storage repository wherein a heat exchanger is horizontallyconfigured.

FIG. 2B is a top view of a preferred embodiment of a thermal energystorage repository wherein a heat exchanger is horizontally configured.

FIG. 2C is a profile view a preferred embodiment of a thermal energystorage repository wherein a heat exchanger is horizontally configured.

FIG. 3A is a top view of another embodiment of a thermal energy storagerepository.

FIG. 3B is a profile view of another embodiment of a thermal energystorage repository.

FIG. 3C is a side view of another embodiment of a thermal energy storagerepository.

FIG. 4 depicts another embodiment of the present invention.

FIG. 5 is a flow diagram for a thermal energy storage method.

DETAILED DESCRIPTION OF THE INVENTION

Detailed embodiments of the present invention are disclosed herein;however, it is to be understood that the disclosed embodiments aremerely exemplary of the invention, which may be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention in virtually any appropriately detailedmethod, structure, or system. Further, the terms and phrases used hereinare not intended to be limiting, but rather to provide an understandabledescription of the invention.

FIG. 1 is an example schematic view of a thermal energy storage system100. The thermal energy storage system 100 comprises a thermal storagemedium 102, a power supply 106 that provides electrical power to anelectrical air heater 108, a heat exchanger 105, an air blower 118, asteam generator 110, a compressor 112, a turbine 114, and an air returnduct 104. The thermal storage medium 102 may be dome-shaped. Arrowsindicate the heat flow direction 120. In one example, in a closed loopsystem, excess heat may be drawn back to the thermal energy storagesystem 100 via the blower 118. In this case, the air blower 118 is areversible air blower. The thermal energy storage system 100 may bedesigned in such a way that air return ducts 104 are used to allow heatto travel back to the thermal storage medium 102, thereby improvingefficiency and reducing loss of heat or energy of the system. Thethermal energy storage system 100 may be a closed-loop system. The powersupply 106 may come from an outside renewable energy resource; therenewable energy resource may be wind or solar power.

FIGS. 2A-C show example preferred embodiments of a thermal energystorage repository 200 wherein an air blower 244, an electrical heater243, and a steam generator 242 are placed in a single heat exchangerduct 238; wherein the heat exchanger duct 238 is horizontallyconfigured. Further, the thermal energy storage repository 200 whereinthe air blower 244, the electrical heater 243, and the steam generator242 are placed in the heat exchanger duct 238; wherein the heatexchanger duct 238 is horizontally configured and the air blower 244,the electrical heater 243, and the steam generator 242 may be radiallyconfigured. The air blower 244, electrical heater 243, and steamgenerator 242 are horizontally positioned in the heat exchanger duct238. The horizontally configured heat exchanger duct 238 with said partsplaced within the heat exchanger duct 238 are positioned in such a waythat leads from the center of the repository to its outer peripherythereby reducing the amount of air ductwork required. In one example,the air blow 244 is positioned on the cool side of the loop. Ahorizontally-oriented steam generator 242 and electrical heater 243module can be easily withdrawn for repairs. A spare steam generator 242and electrical heater 243 module may be inserted into the thermal energystorage repository 200, thus greatly improving the utilization factor ofthe thermal energy storage repository 200. A plurality of horizontallyconfigured heat exchanger ducts 238 may also be used.

FIG. 2A shows a preferred embodiment of a thermal energy storagerepository 200 in the perspective view. FIG. 2B shows a preferredembodiment of a thermal energy storage repository 200 in the top view.FIG. 2C shows a preferred embodiment of a thermal energy storagerepository 200 in the profile view as indicated by a cross sectionalline 252 with two arrows pointed upwards. The thermal energy storagerepository 200 comprises a thermal storage medium 232, a thermalinsulation layer 234, a toroidal return duct 236, a heat exchanger duct238, a central core 240, a steam generator 242, an electrical heater243, an air blower 244, an air return duct 246, pressurized steam toturbine or other industrial process 248, a power supply 250, and animpermeable membrane 262.

The thermal energy storage repository 200 may have a radialconfiguration. The radial configuration helps with storing energy asheat radiates outward from the center. In particular, the thermal energystorage repository may be dome-shaped, tapered or conical-shaped due tothe radial configuration. The dome or conical-shaped thermal energystorage repository 200 is advantageous due to buoyant hot air rising tothe top of the thermal storage medium 232 where it is immobilized by theimpermeable membrane 262. The heat is retained by the thermal insulationlayer 234. The thermal energy storage repository 200 may also beclosed-loop and thereby improving energy efficiency.

In another example, the thermal energy storage repository 200 may alsotake on spherical configuration which may improve efficiency atretaining heat. The thermal storage medium 232 may be a porous particlebed wherein the porous particle bed may be comprised of granite gravel.The thermal storage medium 232 may also comprised of other material orcombinations of materials resulting in a porous particle. In oneexample, the thermal storage medium is made of granite gravel having 5cm diameter particles. In yet other examples, the particles may begreater than or less than 5 cm in diameter. The said particles may takeon a spherical, oval, toroidal, or a combination thereof.

The thermal insulation layer 234 comprises materials suitable to providefurther insulation and thereby helps to retain the buoyant hot airrising. The thermal insulation layer 234 may comprise of differentmaterial composition. In one example, the thermal insulation layer 234has a fiberglass layer positioned on top and a fine silty sand layerpositioned at the bottom. In another example, the thermal insulationlayer 234 has a fiberglass layer positioned on the interior side and afine silty sand layer positioned on the exterior side.

The toroidal return duct 236 may be positioned interior with respect tothe thermal insulation layer 234. The toroidal return duct 236 may bemade of concrete, firebrick, or clay. In one example, the toroidalreturn duct 236 comprises compositions from any two of the concrete,firebrick, or clay material. In another example, the toroidal returnduct 236 comprises concrete, firebrick, and clay. It is noted that thecombination of compositions that make up the toroidal return duct 236may combine in a homogenous manner due to individual materials mixingwell together. However, the toroidal return duct 236 may also compriseregions of individual compositions making up the entirety of thetoroidal return duct 236. The heat exchanger duct 238 may be made ofmaterial that can withstand temperature up to 500° C. In one example,the heat exchanger duct 238 is made of stainless steel. The central core240 may be either an open duct or a vertically-oriented column of largesized particles to allow for enhanced air flow. Central core 240 mayhave low permeability. In one example, central core 240 is perforatedfor radial air flow into the thermal storage medium 232; wherein centralcore 240 takes on a plate-steel structure. In another example, centralcore 240 may comprise of a refractory brick withstanding a maximumtemperature of 800° C.

Steam generator 242 and electrical heater 243 module may be a standardpipe heater exchanger, resistance heater, microwave, or similar heater.The steam generator 242 and electrical heater 243 module may withstand amaximum temperature of 1100° C. The air blower 244 is reversible and maybe made from standard equipment from the power industry. The air blower244 may withstand temperatures of up to 500° C. The air return duct 246may be made of stainless steel. In other examples, the air return duct246 may also be made of standard equipment from the power industry. Thepressurized steam to turbine or other industrial process 248 istransported using standard stainless-steel steam pipes with fiberglassinsulation. The pipes may be able to withstand a maximum temperature of600° C. The impermeable membrane 262 may be made of fiberglass cloth.The impermeable membrane 262 may be made of other insulating material.The member may withstand a maximum temperature of 800° C. The powersupply 250 may be interchangeably referred to as the electrical supplymay come from a high-voltage transmission line. In one example, thepower supply 250 comes from renewable resources. The said renewableresource may further come from solar, wind, or hydro or a combinationthereof.

FIGS. 3A, 3B and 3C show another embodiment of a thermal energy storagerepository 300 with FIG. 3A in the perspective view while FIG. 3B in theprofile view and FIG. 3C is the side view. It should be noted thatcomponents previously presented elsewhere may be similarly presented inFIGS. 3A and 3B.

The thermal energy storage repository 300 comprises a thermal storagemedium 332, a thermal insulation layer 334, a steam generator 344, anelectrical heater 340, an air blower 342, an air return duct 346,pressurized steam to turbine or other industrial process 348, a powersupply 350, and an impermeable membrane 362.

Additionally, the thermal energy storage repository 300 may furthercomprise a toroidal return duct, a central core, and a heat exchangerduct which are not shown in FIGS. 3A and 3B but are show in FIG. 2B, forexample. Notably, the examples in FIGS. 3A and 3B show embodiments of athermal energy storage repository 300 wherein an air blower 312, anelectrical heater 310, and a steam generator 314 are placed in a singleheat exchanger duct; wherein the heat exchanger duct is verticallyconfigured, embedded in the thermal repository and may be centrallocated in the repository.

The thermal energy storage repository 300 may have a radialconfiguration. The radial configuration helps with storing energy hasheat radiates outward from the center. In particular, the thermal energystorage repository may be dome-shaped, tapered or conical-shaped due tothe said radial configuration. The dome or conical-shaped thermal energystorage repository 300 is advantageous due to buoyant hot air rising tothe top of the thermal storage medium 332 where it is immobilized by theimpermeable membrane 362. The heat is retained by the thermal insulationlayer 334. The thermal energy storage repository 300 may also beclosed-loop and thereby improving energy efficiency.

In another example, the thermal energy storage repository 300 may alsotake on spherical configuration which theoretically may improveefficiency at retaining heat.

The thermal storage medium 332 may be a porous particle bed wherein theporous particle bed may comprise of granite gravel. The thermal storagemedium 332 may also comprise other material or combination of materialsresulting in particle bed being porous. In one example, the thermalstorage medium is made of granite gravel having 5 cm diameter particles.In yet other examples, the particles may be greater than or less than 5cm in diameter. The particles may take on a spherical, oval, toroidal,or a combination thereof.

The thermal insulation layer 334 comprises materials suitable to providefurther insulation and thereby helps to retain the buoyant hot airrising. The thermal insulation layer 334 may comprise of differentmaterial composition. In one example, the thermal insulation layer 334has a fiberglass layer positioned on top and a fine silty sand layerpositioned at the bottom. In another example, the thermal insulationlayer 334 has a fiberglass layer positioned on the interior side and afine silty sand layer positioned on the exterior side.

The toroidal return duct may be positioned interior with respect to thethermal insulation layer 304. The toroidal return duct may be made ofconcrete, firebrick, or clay. In one example, the toroidal return ductcomprises compositions from any two of the concrete, firebrick, or claymaterial. In another example, the toroidal return duct comprisesconcrete, firebrick, and clay. It is noted that the combination ofcompositions that make up the toroidal return duct may combine in ahomogenous manner due to individual materials mixing well together.However, the toroidal return duct may also comprise regions ofindividual compositions making up the entirety of the toroidal returnduct. The heat exchanger duct may be made of material that can withstandtemperature up to 500° C. In one example, the heat exchanger duct ismade of stainless steel. The central core may be either an open duct ora vertically-oriented column of large sized particles to allow forenhanced air flow. The central core may have low permeability. In oneexample, the central core is perforated for radial air flow into thethermal storage medium 332; wherein the central core takes on aplate-steel structure. In another example, the central core may compriseof a refractory brick withstanding a maximum temperature of 800° C.

The steam generator 344 and electrical heater 340 module comprises astandard pipe heater exchanger, resistance heater, microwave, or similarheater. The steam generator 344 and electrical heater 340 module maywithstand a maximum temperature of 1100° C. The air blower 312 isreversible and may be made from standard equipment from the powerindustry. The air blower 342 may withstand temperatures of up to 500° C.The air return duct 302 may be made of stainless steel. In otherexamples, the air return duct may also be made of standard equipmentfrom the power industry. The pressurized steam to turbine or otherindustrial process is transported using standard stainless-steel steampipes with fiberglass insulation. The pipes may be able to withstand amaximum temperature of 600° C. The impermeable membrane 362 may be madeof fiberglass cloth. The impermeable membrane 362 may be made of otherinsulating material. The member may withstand a maximum temperature of800° C. The power supply 350 may be interchangeably referred to as theelectrical supply may come from a high-voltage transmission line. In oneexample, the power supply 350 comes from renewable resources. The saidrenewable resource may further come from solar, wind, or hydro or acombination thereof.

FIG. 4 depicts another embodiment of the present invention concerning athermal energy storage repository 400 which may have a top or cover 401that is radial and dome-shaped or conical-shaped. The radialconfiguration minimizes the surface to volume of the repository which,in turn, reduces heat loss.

The angled nature of cap 401 reduces the settling of thermal storagemedium 402, which may be gravel or other material as described above.Settling is an issue since, as the packed bed expands and shrinks underthermal cycling, it may settle, thus reducing the air voids in thepacked bed. Permeable screens 414-416 may be included to prevent gravelfrom moving from and within the repository 400.

Also provided is a heat exchanger 406 connected to blower 409 by duct408. In a preferred embodiment, heat exchanger 406 is embedded withinthe thermal repository 400. Top 401 and heat exchanger 406 include aninsulation barrier 403. An insulated bottom 410 may also be used.Insulation 403 and 410 may be made as described above.

Duct 407, which may be toroidal, is also in communication with airblower 409 and medium 402 through vents 404 and 405. Thus, in operation,heat is added to the repository by employing blower 409 to conduct airvia duct 408 into heat exchanger 406 and then into the thermal storagemedium 402. Heat is extracted by reversing the direction of flow ofblower 409.

FIG. 5 is a flow diagram for a thermal energy storage method. In step502, an amount or threshold of available renewable energy resource ispredetermined to be sufficient to charge the thermal energy storagesystem 100. In step 504, to determine if the amount or threshold of therenewable energy source is reached, an electrical meter may be used.Other sources or meters or sensors may also be used to determine if thethreshold has been reached. A person having ordinary skill in the artmay be able to discern if the predetermined threshold for availablerenewable energy source has been reached. In step 506, if it isdetermined that the available renewable energy source has not reached apredetermined threshold, then the thermal energy storage system 100 isnot charged. The method loops back 508 to step 504.

It is noted that charging of the thermal energy system 100 may refer topowering electrical heater which will heat air blown by the air blower244 or 312. In step 510, if it is determined that the availablerenewable energy source has reached a predetermined threshold, therenewable energy source is used to power the electrical heater. In theenergy charging step 512, air is heated in the center of the repository200 or 300 as in step 514. Heating is expanded radially the region ofstored heat as thermal charging takes place in step 516. The rate ofheating may be adjusted in this step. When energy charging is complete,the method switches to energy storage mode as in step 518. To use theenergy stored, energy discharge takes in place in step 520. In thisstep, the air blower is reversed at 522 and steam is heated in steamgenerator. The speed of the air blower may be adjusted in this step. Therate of heating may also be adjusted in this step. In step 526, thesteam is discharged to steam turbine, district heating, or otherindustrial processes. Once step 520 is complete, the method loops backto step 504.

While the foregoing written description enables one of ordinary skill tomake and use what is considered presently to be the best mode thereof,those of ordinary skill will understand and appreciate the existence ofvariations, combinations, and equivalents of the specific embodiment,method, and examples herein. The disclosure should therefore not belimited by the above-described embodiments, methods, and examples, butby all embodiments and methods within the scope and spirit of thedisclosure.

What is claimed is:
 1. A thermal energy storage system comprising: athermal storage medium; a power supply that provides electrical power toan electrical air heater; a heat exchanger; an air blower; a steamgenerator; a tower; and an air return duct.
 2. The thermal energystorage system of claim 1, wherein the air blower is a reversible airblower to facilitate direction of heat energy.
 3. The thermal energystorage system of claim 1, wherein the power supply comes from arenewable energy source.
 4. The thermal energy storage system of claim3, wherein the renewable energy source comes from solar energy.
 5. Thethermal energy storage system of claim 1 wherein said heat exchanger isembedded in the thermal repository.
 6. A thermal energy storagerepository comprising: a thermal storage medium; a thermal insulationlayer; an air return duct; an electrical heater; a heat exchanger duct;a central core; a steam generator; an air blower; an impermeablemembrane; a power supply; a pipe carrying pressurized steam to turbineor industrial process.
 7. The thermal energy storage repository of claim6, wherein the thermal energy storage medium is dome-shaped.
 8. Thethermal energy storage repository of claim 6, wherein said heatexchanger is embedded in the thermal repository.
 9. The thermal energystorage repository of claim 6, wherein the air blower is reversible tofacilitate direction of heat flow.
 10. The thermal energy storagerepository of claim 6, wherein the power supply comes from a wind. 11.The thermal energy storage repository of claim 6, wherein the powersupply comes from solar.
 12. The thermal energy storage repository ofclaim 6, wherein the air blower, electrical heater, and steam generatorare horizontally positioned in the heat exchanger duct.
 13. The thermalenergy storage method of claim 1, wherein said heat exchanger duct isvertically embedded in the thermal repository and said heat exchangerduct is centrally located in said thermal repository.
 14. A thermalenergy storage method comprising: predetermining a threshold in whichrenewable energy source is sufficient to charge a thermal energy storagesystem; determining if there is renewable energy source available thatmeets the predetermined threshold; using renewable energy source topower an electrical heater; heating air in the center of an energystorage repository; turning of an air blower to store energy for thethermal energy storage system; reversing the air blower and heatingsteam in a steam generator.
 15. The thermal energy storage method ofclaim 14, further comprising discharging the steam to one or a pluralityof other industrial processes.
 16. The thermal energy storage method ofclaim 14, wherein if there is not sufficient renewable energy sourceavailable that meets the predetermined threshold, the electrical heateris not powered.
 17. The thermal energy storage method of claim 14,further comprising adjusting the speed of the air blower.
 18. Thethermal energy storage method of claim 14, further comprising adjustingthe rate of heating the steam in the steam generator.
 19. The thermalenergy storage method of claim 15, wherein said one or a plurality ofother industrial processes comprise turning a steam turbine and districtheating.
 20. The thermal energy storage method of claim 15, furthercomprising re-determining if there is renewable energy source availablethat meets the predetermined threshold subsequent to discharging thesteam to one or a plurality of other industrial processes.
 21. Thethermal energy storage method of claim 14 further including a heatexchanger duct that is vertically embedded in said energy storagerepository and said heat exchanger duct is centrally located in saidenergy storage repository.
 22. The thermal energy storage method ofclaim 14, wherein the air blower, electrical heater, and steam generatorare horizontally positioned in the heat exchanger duct.